The present invention relates to the finish for polyamide yarn. The finish of the invention comprises ingredients, which function to prevent oligomer extraction from the interior of polyamide yarn during storage, base components, and additives.
Polyamide yarn stored at high temperature and humidity for a long time sometimes causes fluffs or yarn breakage, in down-stream processes such as, twisting, texturing, warping, sizing, weaving, and knitting, due to high friction at yarn-to-machinery interface and fluctuated yarn tension by the said high friction.
The high friction at yarn-to-machinery interface is caused by the scum deposited on the surface of machine parts such as, guides, rolls, combs, or needles. The scum comprises the oligomer extracted from the inside to the surface of polyamide-yarn by the moisture which has penetrated into the polyamide yarn through the uncrystallized part of the polyamide yarn during long-term storage especially under high temperature and humidity.
Finishes for polyamide yarn are applied in neat, solvent dilution, or 5-30% aqueous emulsion in spinning process. And finish-applied yarn is taken up into packages in spin-draw system, where finish-applied yarn is drawn between 1st and 2nd godet rolls at a fixed draw ratio, or in highly-oriented yarn (HOY) production system, where finish-applied yarn is not drawn before take-up.
Recently the spinning speed of polyamide yarn has been increased for better cost performance. Increased spinning speed accelerates the above-mentioned loosening of polymer orientation at the uncrystallized part of polyamide yarn, and thus increases the moisture penetrating into polyamide yarn through the said uncrystallized part.
Increased moisture penetrated into polyamide yarn increases the oligomer extraction out on yarn surface, and thus leads to the increase of fluffs and yarn breakage in down-stream process due to scum generation.
The finish of the present invention will prevent the oligomer extraction from the interior to the surface of polyamide yarn, and will minimize or eliminate troubles in the down-stream process, i.e., fluffs and yarn breakage.